1. Field of the Invention
The present invention relates to LED packaging technology and more particularly, to a LED packaging method using a screen plate, which simplifies LED package manufacturing process, raises LED package production efficiency, and reduces the related equipment cost.
2. Description of the Related Art
The fabrication of a LED package includes a procedure of packaging a LED chip with a fluorescent adhesive. The fluorescent adhesive packaging procedure may be achieved by means of a dot gluing or casting procedure. Applying a dot gluing procedure to package LED chips may encounter the problems of dimension error and adhesive displacement. A casting procedure eliminates the problems of dimension error and adhesive displacement, however it tends to cause a stress, resulting in an imperfect contact between the LED chip and a substrate or falling of the LED chip from the substrate. Further, the equipment cost for casting packaging is high.
In view of the aforesaid drawbacks, a screen-printing technique is created to apply a fluorescent adhesive to LED chips. A screen plate for this purpose has multiple through holes made subject to a predetermined dimension to limit the applied packaging adhesive. This method improves packaging accuracy and quality of emitted light. Further, a screen-printing packaging method has the advantages of low cost and fast production speed. Because a screen-printing packaging method eliminates the problem of stress, it has high reliability.
Although a LED package made by means of the aforesaid conventional screen-printing packaging method has optimal light output quality and reliability, the aforesaid conventional screen-printing package method is insufficient to satisfy advanced LED package designs. For packaging a LED package having multiple fluorescent adhesive layers and light transmissive layers, different screen plates of different mesh sizes must be used in a proper order to print a respective layer. This manufacturing process is complicated, increasing the equipment cost and lowering the production efficiency and having less economic effect.